This invention relates to new benzimidazole derivatives having a cardiotonic effect, to processes for the preparation thereof and to pharmaceutical compositions comprising said derivatives.
Japanese Patent LOP Publn. No. 215388/1986 discloses benzimidazole derivatives having a gastrosecretoinhibitory effect.
Japanese Patent LOP Publn. No. 123115/1987 discloses benzimidazole derivatives having a cytoprotection from gastric acid.
However, the benzimidazole derivatives disclosed above are the compounds wherein the benzimidazole group is attached, through --S--, --SO.sub.2 -- or --S.fwdarw.O, to a pyridyl group or a phenyl group. These compounds are quite different in chemical structure and pharmacological effects from the compounds of the below-mentioned formula (I) according to the present invention wherein the benzimidazole group is attached, through --CO--, to a heterocyclic group.
Further, other benzimidazole derivatives are mentioned in J. Chem. Soc. (C) 25-29 (1967) and Chem. Ber. 105, 337-352 (1972), but these derivatives are different in chemical structure from the compounds of the invention. There is no mention therein of the pharmaceutical use for these derivatives.